Raymundo Amorim

Published works

The list of published papers and awards & nominations. You can find more information related to each articles/awards on the photo.

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Awards & Nominations

Morphogenetic Metasurface Antennas for Secure Identification; IEEE Antennas and Wireless Propagation Letters

Chipless Image-Based System for Spatial-Frequency Data Encoding; IEEE Transactions on Antennas and Propagation

Abstract

This paper discusses a bistatic reading configuration that employs a frequency-spatial encoding strategy to enhance the data encoding capacity in chipless radio frequency identification (RFID) systems. The proposed method allows for the estimation of resonant frequencies associated with each scatterer and the determination of relative resonator positions. The approach relies on an imaging algorithm that evaluates the positions of the resonators by considering a single-frequency point corresponding to the resonant frequency of each scatterer. Consequently, the proposed method does not seek to image the shape of the metal scatterers but rather to locate their positions geometrically for different frequencies. Indeed, once the resonance frequencies have been detected, a geometric representation of the backscattered field is created by limiting the observable frequency band to the resonance frequencies. The use of individual processing with single-frequency steps enables the distinction of the side-by-side gap between resonators, even at resolutions below the conventional image resolution. Furthermore, this method has the capability to differentiate the gap spacing, which can be as small as $\lambda/8$, between resonators operating at different resonance frequencies. This technique significantly increases the coding capacity associated with the chipless tag. A proof of concept (PoC) is evaluated based on loop resonators for identification purposes. Then, anechoic and real scenario measurements (3D displacement table and conveyor belt) are considered in different acquisition configurations. An office environment reading range of up to 20 cm has been reported.

Optimal Angle in Bistatic Measurement for Chipless Tag Detection Improvement; IEEE Transactions on Antennas and Propagation

Abstract

This article shows the use of a bistatic reading configuration by optimizing the angle between the two antennas, which allows isolating the contribution of the radio frequency identification (RFID) chipless tag from its nearby environment, thus enhancing the reading performance of the chipless tag for short-range applications. The idea is to extract as much useful signal (relating to the tag information or tag ID) from the total signal using a dedicated bistatic reading configuration. This extraction step is implemented from a hardware point of view, which is different from classical approaches based on signal processing. Indeed, based on this technique, it is possible to read tags even in highly reflective environments (metallic surfaces) without applying a calibration method, such as subtracting the environment without the tag or advanced postprocessing steps. For this purpose, a bistatic antenna configuration is employed, where the angle between the incident wave and the backscattered signal is chosen to maximize copolarization configuration. First, a model based on the general scatter theory is evaluated; it highlights the scattering mechanism involved in the problem. Then, a proof of concept (PoC) is evaluated, and afterward, a chipless tag composed of an array of dipoles is studied for identification purposes. The analytical evaluation and the channel modeling allow a general implementation of the proposed technique. Anechoic and real scenario measurements are evaluated considering the presence of surrounding objects. Finally, nonsystematic errors related to the positioning of the tag are considered each time without considering a reference (or background) measurement or the use of specific signal processing techniques.

Millimeter wave chipless RFID authentication based on spatial diversity and 2-D classification approach; IEEE Transactions on Antennas and Propagation

Abstract

In this article, a millimeter-wave (mmWave) chipless radio-frequency identification (RFID) tag is developed to operate in the V-band for authentication applications. A novel approach based on tag backscattered E-field measurements at different orientation angles for unitary classification is proposed. The concept is based on the hardness to identically reproduce materials due to the inherent randomness in the fabrication process. These uncertainties are transcribed in very small variations that can be observed in the tag electromagnetic response. A set of 16 identical tags were fabricated, and each tag shares the same fabrication mask and manufacturing process method. Spatial diversity using the tag backscattering pattern (at two different angles) adds independent characteristics for estimating authenticity of each tag. To better exploit the large amount of data collected with this approach, a machine learning (ML) sighting classification is used, which enhances the system performance. The probability of error (PE) achieved with the method is around 1%. This PE is four times lower than the one obtained with a similar approach implemented in the X-band.

A new method of secure authentication based on electromagnetic signatures of chipless RFID tags and machine learning approaches; MDPI Sensors

Abstract

In this study, we present the implementation of a neural network model capable of classifying radio frequency identification (RFID) tags based on their electromagnetic (EM) signature for authentication applications. One important application of the chipless RFID addresses the counterfeiting threat for manufacturers. The goal is to design and implement chipless RFID tags that possess a unique and unclonable fingerprint to authenticate objects. As EM characteristics are employed, these fingerprints cannot be easily spoofed. A set of 18 tags operating in V band (65-72 GHz) was designed and measured. V band is more sensitive to dimensional variations compared to other applications at lower frequencies, thus it is suitable to highlight the differences between the EM signatures. Machine learning (ML) approaches are used to characterize and classify the 18 EM responses in order to validate the authentication method. The proposed supervised method reached a maximum recognition rate of 100%, surpassing in terms of accuracy most of RFID fingerprinting related work. To determine the best network configuration, we used a random search algorithm. Further tuning was conducted by comparing the results of different learning algorithms in terms of accuracy and loss.

Simple Low Cost Open Source UHF RFID Reader; IEEE Journal of Radio Frequency Identification

Chipless RFID Tag Imaging System based on Conveyor-Belt Radio Frequency Scanning; IEEE CAMA 2023

Morphogenetic Metasurface Engineering for Computational Localization Applications; IEEE CAMA 2023

3D Authentication Approach to Enhance the Security Level for Millimeter-wave Chipless Tags; IEEE RFID TA 2023

Bistatic Configuration Reading for Sub-Millimeter Displacement Chipless Tag Sensor; EuCAP 2023

Design and Manufacture of Resonant Chipless Tags in Millimeter-Wave Band; IEEE RFID TA 2022

Diversité spatiale pour l'augmentation de la robustesse de détection des tags RFID sans puce; JNM 2022

Millimeter-wave Chipless RFID Tag for Authentication Applications; EuMW 2020

Abstract

This paper presents a millimeter-wave chipless RFID tag for authentication applications. The concept is based on the idea that it is extremely difficult to identically reproduce materials that inherently have a random aspect due to manufacturing process variations. This paper introduces the paradigm of millimeter-wave authentication based on tags without any chip, including an identifier capable of communicating in the millimeter-wave range. For this purpose, millimeter-wave chipless tags without a ground plane are designed using the RF Encoding Particle (REP) technique. This approach establishes a relation between the geometrical parameters of the isolated scatter and its electromagnetic signature. An elementary particle multiplication strategy is envisaged to increase the backscattered tag level. The evaluated probability of error around 17% is reached with a fabricated tag set from the same manufacturer simultaneously. This probability is two times lower than the one obtained with a similar approach implemented in the X-band.

Soil Moisture Sensor with a Microstrip Band Stop Filter; WF-IoT 2020

Negative Group Delay Folded Circuit with Distributed Broadside Parallel Line; IEEE APS 2019

Analysis of Electromagnetic Interference in Electric Vehicle Cables; IEEE APS 2018

Low-cost folded chipless tag for millimeter-wave applications; IEEE APS 2018

Design and implementation of a measurement system for characterization of reverberation chamber; I2MTC 2018

Matching improvement of an asymmetric biomimetic antenna array for source locating; RWW 2018

Bandwidth Enhancement of an Ultra Wide Band Planar Inverted F-Antenna; SBrT 2018

Increased sensivity of tracking of portable devices based on biological organisms; IMOC 2015

Abstract

In this study a miniaturized asymmetric planar antenna array was built and analyzed. In order to reduce the coupling between the elements and to improve the impedance matching of the array two techniques were employed: slightly shifted one of the elements and use a ferrite based transformer. In the design, the miniaturization is achieved by placing the elements of the arrangement closed to each other (≤ ƛ/2). The concept is based on the ability of some insects, which have very small physical dimensions compared to the wavelength of the communication signal, to detect other insects of the same species. This is the case of the fly Ormia ochracea that has high ability to control the phase difference of the received signals. For practical applications, a prototype of a planar Bow-tie antenna was built on Rogers TMM6 substrate to operate around 300 MHz. The measures show reflection coefficient below -10 dB and coupling coefficients around -20 dB, within the desired range. It was carried out using the vector network analyzer (R&S ZVB20).

IEEE CRFID James Clerk Maxwell Best Journal Paper Award 2024; IEEE CRFID

Thesis award nomination URSI France 2024; URSI France

2023 IEEE Industrial Engineering Paper Award on Antenna Measurements and Applications; IEEE CAMA 2023

IEEE RFID 2022 Best poster award; IEEE RFID 2022